Cadmium Absorption in Mice: Effects of Broiling on Bioavailability of Cadmium in Foods of Animal Origin

The absorption and organ distribution of organic Cd from raw and broiled horse kidney was compared to that of CdCl₂ at two dose levels (0.05 and 3 mg Cd/kg feed) in a feeding study in mice. The high Cd concentration in the horse kidney (raw 112 mg/kg; broiled 53 mg/kg) made it possible to mix kidney into mouse feed without marked effects on the composition of the feed. The weight of the mice, feed and water consumption, and Cd levels in the feed were determined once a week. After 9 wk of exposure, the liver and kidneys of the mice were sampled and Cd was analyzed. The Cd concentration in horse kidney was halved by broiling, and the content of soluble Cd decreased from 12% in raw kidney to 5% in broiled kidney. The majority of the soluble Cd was associated with proteins with the same molecular weight as metallothionein (MT) in both raw and broiled kidney. Broiling of the kidney had no marked effect on the fractional accumulation of organic Cd in mice. The fractional accumulation of inorganic CdCl₂, on the other hand, was significantly higher than that of organic Cd in the low dose groups but not in the high dose groups. The ratio between Cd accumulation in kidney and that in liver was higher in the group receiving raw kidney compared to the ratio in the group receiving CdCl₂ at both the high and low exposure levels. This indicates that the raw kidney contained a Cd form that was more preferentially distributed to the kidneys.